[Code]
procedure InitializeWizard;
var
  LineIndex: Integer;
  StringList: TStringList;
begin
  StringList := TStringList.Create;
  try
    StringList.LoadFromFile('c:\SomeFile.xxx');
    if StringList.Find('Line text to find', LineIndex) then
    begin
      StringList[LineIndex] := 'Modified line text';
      StringList.SaveToFile('c:\SomeFile.xxx');
    end;
  finally
    StringList.Free;
  end;
end;